1. Technical Field
The present invention relates to dentures and false teeth, which may preferably improve occlusion (i.e., the fitting together of the teeth of the lower jaw with the corresponding teeth of the upper jaw when the jaws are closed). The present invention also relates to methods for aligning dentures and false teeth. Further, the present invention relates to methods for treating and preventing maladies caused by malocclusion using the herein described dentures and false teeth.
2. Description of Related Art
Recent research has considered the relationship between malocclusion and geineralized symptoms (e.g., headaches, stiff shoulders, and back pain). There have already been reports of an improvement in various generalized symptoms through the correction of occlusion in patients fitted with full dentures or a splint in the oral cavity (see e.g., Nakamura, Shoji, xe2x80x9cFactors of Occlusion-Related Diseases and Diagnosis and Treatment Thereof,xe2x80x9d P.J.A. Occlusion Health, Vol. 1 (1995)).
Known dentures are designed and produced so as to have the shape and function of natural human teeth because the dentures serve as a replacement for natural teeth. An examination of the shape of the occlusal surface of known false molars also reveals a shape that is designed and produced to be identical to the occlusal surface of natural molars (premolars and molars).
However, the configuration of dentures fitted with individual teeth identical in shape and function to natural teeth has been unable to provide preferred occlusion in patients requiring dentures. Even though the individual teeth satisfactorily perform the intended function, this alone is not adequate. Instead, dentures must provide appropriate occlusion in order to function satisfactorily.
Previously, little thought was given to the balance in occlusal force (between, for example, adjacent molars and corresponding left/right molar pairs) during occlusion of the denture as a whole or at the center of occlusion. Therefore, wearing the denture worsened occlusion and produced various unpleasant conditions caused by malocclusion.
Development is therefore needed of not just individual false teeth, but also false teeth (molars) having a shape that considers the balance in occlusal force during occlusion (mastication) in order to prevent generalized symptoms associated with malocclusion. In addition, the development of a treatment that can prevent or cure malocclusion, and the associated generalized symptoms, also has been a long felt need.
When implanting a false tooth or denture, a dental technician or dentist must adjust the occlusal surface of the false teeth so as to appear natural in consideration of the dentition and occlusion of the recipient. Thus, the shape of the occlusal surface sometimes must be significantly modified by cutting. Moreover, after adjustment of the occlusal surface following implantation, the actual occlusion of the wearer will gradually change due to mastication and other various daily habits that affect occlusion.
If the occlusal surface is composed of a material that is hard or has a high wear resistance, cutting is problematic and the dental technician or dentist can not easily make initial occlusal adjustments. Further, such hard materials do not wear down in response to changes in the occlusion of the individual wearer, thereby creating a malocclusion. Moreover, improper occlusion is difficult to correct by cutting, due to the hardness of the occlusal surface.
It is, accordingly; one object of the present invention to provide improved false teeth and dentures.
Due to the perceived relationship between malocclusion and generalized symptoms apparently caused by malocclusion, the present teachings provide an occlusal configuration that readily maintains overall balance in occlusal force during occlusion. As a result, false teeth and dentures are described that are suitable for attaining preferred occlusion. Herein, preferred occlusion refers to a configuration for attaining opposed-tooth (or teeth) contact at the four points corresponding to the left and right upper second premolars and first molars. Preferably, the opposing teeth contact at four points from the lingual cuspals of the left and right upper second premolars to the proximal lingual cuspals of the upper first molars. Consequently, the present false teeth and dentures can prevent or substantially reduce the possibility of malocclusion and therefore, improve the satisfaction of the wearer.
In one aspect of the present teachings, dentures may have one or more false teeth selected from the upper and lower second premolars and first molars. The false tooth or teeth preferably have the following characteristics in relation to the upper and lower second premolars and first molars other than the false tooth or teeth named above:
(1l ) an imaginary plane passing through the supporting cuspals of the upper second premolars and the supporting cuspals of the upper first molars may be parallel or substantially parallel to the occlusal plane;
(2) an imaginary plane passing through the base of the opposed-teeth contact region formed on the occlusal surface of the lower second premolars and the lower first molars may be parallel or substantially parallel to the occlusal plane; and
(3) in centric occlusion, the supporting cusps of the upper second premolars and the supporting cusps of the upper first molars may contact the bases of the respective opposed-teeth contact regions formed on the occlusal surface of the lower second premolars and the lower first molars.
If the above characteristics are utilized, the dentures may have the above-mentioned preferred occlusal configuration, which thereby provides balance during occlusion to the occlusal region extending from the upper and lower second premolars to the first molars. Further, the denture may maintain balance in occlusal force in all horizontal directions while the wearer is biting down and prevents occlusal force from becoming unbalanced in any horizontal direction. Thus, the occurrence of generalized symptoms connected to malocclusion are reduced or prevented. Such generalized symptoms discovered to result from improper occlusion include headaches, such as migraine headaches and stress-related headaches, stiff shoulders, lumbago, backaches, sore knees, shaking, numbing, and pain of the limbs, sore eyes, asthenopia, myodesopsia, tinnitus, hearing difficulties, insomnia, lethargy and hypertension.
Another aspect of the present teachings provides false teeth that may be utilized in the above-described dentures. Further, representative methods for making such dentures are taught that will provide the first through third occlusal configurations noted above.
In another aspect of the present teachings, representative methods for improving and treating occlusion-related conditions using one of the dentures of the invention are taught. In addition, methods for preventing occlusion-related conditions are taught using the present denture. More specifically, adjusting occlusion to bring about one of the above occlusal configurations using the present dentures improves or prevents conditions thought to arise in relation to occlusion (hereinafter referred to as occlusion-related conditions).
Another aspect of the present teachings provides a multi-layered false tooth that is formed from two or more layers in which the inside of the second or greater occlusal-surface-side layer has an internal layer that has a wear resistance and/or hardness greater than the wear resistance and/or hardness of the first occlusal-surface-side layer. As a result, wear of the false tooth is suppressed in the internal layer even when wear associated with mastication and other daily habits related to occlusion by the wearer of the false tooth has been caused in the first layer. Excessive wear of the occlusal surface and excessive occlusal variation are avoided by virtue of the internal layer. Such false teeth therefore provides satisfactory occlusion in individual wearers. Preferably, the false tooth adequately avoids wear as a result of such an internal layer.
Another aspect of the present teachings provides an implant comprising at least one false tooth of one of the above embodiments.